118 Mr. T. Andrews. [June 5, 



condition was to some slight extent modified, magnetism acting 

 through considerable periods of time apparently exerting a measurable 

 influence. For conducting the present investigation he devised, and, 

 after careful consideration, decided to adopt, the delicate electro- 

 chemical method of research hereafter described, and by the use of a 

 sensitive astatic mirror galvanometer and other appliances the follow- 

 ing results wei-e obtained, which it is hoped may prove of interest and 

 afford an addition to our knowledge of some of the conditions affect- 

 ing the passive state of iron and steel. 



For convenience, the experiments are classified under the following 

 heads : 



Series I, Table I, containing the result of observations on the 

 influence of magnetisation on the passive state of steel in cold nitric- 

 acid, sp. gr. 1'42, at temperature of 45 F. or less. 



Series II, Table II, treating of the influence of magnetisation on 

 the passive state of steel in warm nitric acid, sp. gr. 1'42, above the 

 temperature of 45 F., the experiments showing that magnetised 

 steel bars were less passive in warm nitric acid than unmagnetised 

 ones. 



Chemical Analysis of the Steel Bars. 



per cent. 



Combined carbon 0*570 



Silicon 0-032 



Sulphur . , trace 



Phosphorus 0'066 



Manganese 0'147 



Iron (by difference) 99185 



Total 100-000 



Physical Properties of the Steel Bars. 



SERIES I. 



The Influence of Magnetisation on the Passive State of Steel in Cold 



Nitric Acid. 



The method of experimentation for the observations of Series I was 

 as follows : 



